• Journal of Periodontal and Implant Science
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• 제44권2호
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• pp.50-56
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• 2014

Purpose: The aims of this study were to measure the distance of the intraosseous vascular anastomosis in the anterolateral wall of the maxillary sinus from different reference points, and to correlate the location of the intraosseous vascular anastomosis with the tooth position and the residual bone height of the maxilla. Methods: Computed tomography (CT) images were taken from 283 patients undergoing dental implants placement in the posterior maxilla. Three horizontal lines were drawn at the ridge crest, maxillary sinus floor, and the position of the anastomosis. A vertical second line at the center of each tooth was drawn perpendicular to the horizontal lines. The distance from the ridge crest to the maxillary sinus floor and the distance from the maxillary sinus floor to the bony canal were measured from the intersections of the horizontal and vertical lines. The residual alveolar bone height was used to categorize three groups: group 1,<4 mm; group 2, between 4 and 8 mm; and group 3, >8 mm. Results: The residual bone height values of different tooth positions were significantly different (P=0.0002). The distance from the maxillary sinus floor to the intraosseous vascular anastomosis was significantly different between groups 1 and 3 (P=0.0039). At the molar sites, a moderate negative correlation was found between the residual bone height and the distance from the maxillary sinus floor to the intraosseous anastomosis. The distances of the alveolar ridge crest and the maxillary sinus from the intraosseous vascular anastomosis were not significantly different between sexes. Conclusions: Within the limitations of this study, sites with a higher residual bone height in the molar regions were at a relatively high risk of artery damage during window osteotomy preparation; therefore, we recommend taking more precautions when using a lateral approach for sinus elevation.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.373-376
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• 2006

In general, a method for generating irregular wave by combination of component waves obtained from linear wave theory is widely used. In these method, however, mean water surface elevation is rising from time to time because of nonlinear effect of wave. In this study, for the rising problem of mean water surface elevation and stabilization of calculation from time to time, mass transport velocity for horizontal velocity at wave source position is considered. The rising problem of mean water surface elevation is checked by comparing calculated wave profile from numerical technique proposed in this study with target wave profile at wave source position in numerical wave tank by using CADMAS-SURF code. And, by generating irregular wave, the validity of wave overtopping rate estimated from this numerical analysis is discussed by comparing computed results with measured results in hydraulic model experiments for vertical seawall located on a sloping sea bottom. As a results, the computations are validated against the previously experimental results by hydraulic model test and numerical results of this study and a good agreement is observed. Therefore, numerical technique of this study is a powerful tool for estimating wave overtopping rate over the crest of coastal structure.

• 물과 미래
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• 제29권2호
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• pp.153-165
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• 1996

월류흐름을 포함하는 1차원 부정류 계산모형으로서 월류흐름에 대한 국소적 처리기법을 포함한 단일하도 모형 및 폐합형 수계에 모형을 각각 구성하여, 월류부를 포함한 시험하도 문제에 적용함으로써 모형의 적용성을 조사하였다. 역방향 흐름을 포함한 다양한 형태의 월류흐름이 잘 모의되었으며, 월류구조물의 표고가 높아서 실질적으로 흐름이 존재하지 않는 경우도 성공적으로 모의되었다. 자유월류형 역방향 흐름은 폐합형 모형에 의해서 뿐만 아니라 단일하도 모형에 의해서도 모의될 수 있음이 입증되었다.

• 대한토목학회논문집
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• 제41권6호
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• pp.663-673
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• 2021

해안구조물 설계시 허용평균월파량은 설계요소중의 하나이며, 구조물의 마루높이는 구조물의 안전, 보행자의 안전 및 운영 등에 요구되는 월파량 이하가 되도록 하여야 한다. 최근 들어 보다 안전한 설계를 위해 평균월파량보다 개별 최대월파량을 기준으로 적용하자는 제안이 이루어지고 있다. 본 연구는 비쇄파조건에서 개별 최대월파량에 대한 정보를 제공하고자 하는 것이며, 경사식구조물의 기하학적 형상을 고려안 2차원 수리모형실험을 수행하였다. 또한 실험을 위해 새로운 계측방법을 고안하였다. 실험결과를 이용하여 평균월파량에 기반하여 개별 최대월파량을 산정할 수 있는 경험식을 제안하였다. 그리고 피복재 어깨폭에 따른 평균월파량의 저감효과에 대해서도 검토하였다.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.142-149
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• 2019

본 연구에서는 인천광역시 중구 을왕동 충의휴양소 전면 해역에서의 과거 침식이력 및 현황을 세밀히 조사하고 해안선 침식원인을 찾기 위해 파랑 및 해빈류 등을 조사하여 분석 하였다. 관측결과 유의파고($H_{1/3}$)는 0.07~1.57 m의 범위로 나타났고, 평균값은 0.21 m로 나타났다. 또한 최대파고($H_{max}$)는 0.02-4.76m 범위로 나타났고, 평균값은 0.27 m로 나타났다. 파랑변형 수치모형실험을 통해 법선파고 및 주기를 산정하였고, 50년 빈도 설계파고는 0.82 m~3.75 m의 범위를 나타내었다. 해빈류 실험 결과 이안제 및 도류제 설치 이후 충의 휴양소 해안 부근의 해빈류가 감소하는 경향을 나타냈다. 반면, 마루높이를 5 m까지 높였을 경우에는 큰 변화가 없었지만 8m로 높이면 낮아진 수심의 영향으로 강한 해빈류가 수중방파제 주변에 발생하였다. 또한, 충의휴양소의 주된 침식원인은 외해로부터 입사하는 파랑특성이 백사장 전면에 집중적으로 내습하기 때문이다. 백사장 전면으로 집중되는 파의 변형으로 백사장과 평행하게 흐르는 연안류와 횡단방향으로의 이안류를 추가적으로 유발시킴으로써 연안표사가 전면외해로 이동/유출하기 때문으로 확인할 수 있었다. 본 연구의 결과는 백사장 원상복구 및 효율적인 침식방지시설 선정의 기초자료로 활용될 수 있을 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.345-359
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• 2006

Loss of maxillary molar teeth leads to rapid loss of crestal bone and inferior expansion of the maxillary sinus floor (secondary pneumatization). Rehabilitation of the site with osseointegrated dental implants often represents a clinical challenge because of the insufficient bone volume resulted from this phenomenon. Boyne & James proposed the classic procedure for maxillary sinus floor elevation entails preparation of a trap door including the Schneiderian membrane in the lateral sinus wall. Summers proposed another non-invasive method using a set of osteotome and the osteotome sinus floor elevation (OSFE) was proposed for implant sites with at least 5-6mm of bone between the alveolar crest and the maxillary sinus floor. The change of grafted material in maxillary sinus is important for implant survival and the evaluation of graft height after maxillary sinus floor elevation is composed of histologic evaluation and radiomorphometric evaluation. The aim of the present study was radiographically evaluate the graft height change after maxillary sinus floor elevation and the influence of the graft material type in height change and the bone remodeling of grafts in sinus. A total of 59 patients (28 in lateral approach and 31 in crestal approach) who underwent maxillary sinus floor elevation composed of lateral approach and crestal approach were radiographically followed for up to about 48 months. Change in sinusgraft height were calculated with respect to implant length (IL) and grafted sinus height(BL). It was evaluated the change of the graft height according to time, the influence of the approach technique (staged approach and simultaneous approach) in lateral approach to change of the graft height, and the influence of the type of graft materials to change of the graft height. Patients were divided into three class based on the height of the grafted sinus floor relative to the implant apex and evaluated the proportion change of that class (Class I, in which the grafted sinus floor was above the implant apex; Class II, in which the implant apex was level with the grafted sinus floor; and Class III, in which the grafted sinus floor was below the implant apex). And it was evaluated th bone remodeling in sinus during 12 months using SGRl(by $Br\ddot{a}gger$ et al). The result was like that; Sinus graft height decreased significantly in both lateral approach and crestal approach in first 12 months (p$MBCP^{TM}$ had minimum height loss. Class III and Class II was increased by time in both lateral and crestal approach and Class I was decreased by time. SGRI was increased statistically significantly from baseline to 3 months and 3 months(p<0.05) to 12 months(p$ICB^{(R)}$ single use, more reduction of sinusgraft height was appeared. Therefore we speculated that the mixture of graft materials is preferable as a reduction of graft materials. Increasing of the SGRI as time goes by explains the stability of implant, but additional histologic or computed tomographic study will be needed for accurate conclusion. From the radiographic evaluation, we come to know that placement of dental implant with sinus floor elevation is an effective procedure in atrophic maxillary reconstruction.

• 한국해양공학회지
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• 제22권5호
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• pp.44-51
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• 2008

The planning and design of coastal structures against wave attack is required to accurately predict wave transformation, wave run-up, and fluid. particlevelocities an a slope. On tire other hand, in tire swash and surf zones of a natural beach, where coastal erosion and accretion occur at tire land-sea boundary, hydrodynamic analysis is essential. In this study, a RBREAK2 numerical model was created based on the nonlinear shallow water equation and laboratory measurements were carried out in terms of tire free surface elevations and velocities for tire cases of regular and irregular waves on 1 : 10 and 1 : 5 impermeable slopes. The data were used to evaluate tire applicability and limitations of tire RBREAK2 numerical model. The numerical mode1 could predict tire cross-shore variation of the wave profile reasonably well, but showed more accurate results for slopes that were steeper than 1 : 10. Except near tire wave crest, tire computed depth averaged velocities could represent tire measured profile below tire trough level fairly well.

• 패션비즈니스
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• 제19권6호
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• pp.28-41
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• 2015

Properties of textile fabrics influence the appearance, aesthetics, and performance of garment. Drape and related properties of fabrics affect profoundly the static and dynamic appearance during wearer's movement. The three dimensional shape of the folded structure often deforms with time or with subtle vibration around the fabric specimen during the drape measurement. Due to the uneven and complex nature of fabrics, the overall shape of the fabric specimen on the drape tester often becomes unstable. There is a need to understand the fundamental mechanisms of how draping may generate pleasing forms. Two drape test methods, conventional Cusick drape test, and in-built drape tester, based on a depth camera, are compared. Fabric specimens including cotton, linen, silk, wool, polyester, and rayon are investigated for the fabric drape and other physical/mechanical parameters. Drape coefficient values of fabric specimens are compared based on the final drape images, together with the intermediate 3D drape images of the specimens during elevation process of the drape tester equipped with a stepper motor system. The correlation coefficient between the data based on the two methods is reasonably high. Another advantage from the depth camera system is that it allows further analysis of three-dimensional information regarding the fabric drape shape, including the shape of nodes or crest and trough.

• Archives of Plastic Surgery
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• 제42권5호
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• pp.580-587
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• 2015

Background Descent of the lateral aspect of the brow is one of the earliest signs of aging. The purpose of this study was to describe an open surgical technique for lateral brow lifts, with the goal of achieving reliable, predictable, and long-lasting results. Methods An incision was made behind and parallel to the temporal hairline, and then extended deeper through the temporoparietal fascia to the level of the deep temporal fascia. Dissection was continued anteriorly on the surface of the deep temporal fascia and subperiosteally beyond the temporal crest, to the level of the superolateral orbital rim. Fixation of the lateral brow and tightening of the orbicularis oculi muscle was achieved with the placement of sutures that secured the tissue directly to the galea aponeurotica on the lateral aspect of the incision. An additional fixation was made between the temporoparietal fascia and the deep temporal fascia, as well as between the temporoparietal fascia and the galea aponeurotica. The excess skin in the temporal area was excised and the incision was closed. Results A total of 519 patients were included in the study. Satisfactory lateral brow elevation was obtained in most of the patients (94.41%). The following complications were observed: total relapse (n=8), partial relapse (n=21), neurapraxia of the frontal branch of the facial nerve (n=5), and limited alopecia in the temporal incision (n=9). Conclusions We consider this approach to be a safe and effective procedure, with long-lasting results.

• Restorative Dentistry and Endodontics
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• 제42권3호
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• pp.240-252
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• 2017

The restoration of endodontic tooth is always a challenge for the clinician, not only due to excessive loss of tooth structure but also invasion of the biological width due to large decayed lesions. In this paper, the 7 most common clinical scenarios in molars with class II lesions ever deeper were examined. This includes both the type of restoration (direct or indirect) and the management of the cavity margin, such as the need for deep margin elevation (DME) or crown lengthening. It is necessary to have the DME when the healthy tooth remnant is in the sulcus or at the epithelium level. For caries that reaches the connective tissue or the bone crest, crown lengthening is required. Endocrowns are a good treatment option in the endodontically treated tooth when the loss of structure is advanced.